This invention relates to a method and an apparatus for dicing a substrate, and more particularly to, a method and an apparatus for dicing a substrate by a laser beam irradiation process.
These days, the development of devices in which electronic circuits, optical circuits etc. are provided on a substrate, such as glass material, magnetic material, semiconductor material, or dielectric material substrate, has been activated. From several to several thousand devices are formed in, and/or on a surface or back side of the substrate, so that it must be diced, i.e. be cut and divided into each pieces of the devices at the final step of the process.
A conventional method for dicing a substrate comprises setting a substrate on a stage by a vacuum system, irradiating a laser beam, such as CO.sub.2 (carbon dioxide) laser beam, on the substrate with blowing off gas using a guide, and moving the stage so that the laser beam is irradiated to follow a track for dicing, wherein the laser beam is focused at a surface of the substrate.
In the conventional method for dicing a substrate, however, there is a disadvantage in that many undesirable micro-cracks develop, due to thermal deformation stress, on a surface, a back side or a diced plane of the substrate. Therefore, the surfaces of the diced planes are not flat. Another disadvantage is that it is difficult to dice the substrate closely following the tracks on which the laser beam is irradiated.